If you are using your tablet as a media device: Kindle Fire HD.
If you are using your tablet as a portable computer: Nexus 7.
If you care at all about the underlying Android OS: Nexus 7.
If you are primarily buying this tablet for your family: Kindle Fire HD.
If you own a LOT of Amazon content: Kindle Fire HD.

I'd say bust out the pro/con chart for each device and decide that way. I know personally I would never be able to put up with the performance inadequacies that the original Kindle Fire had, and haven't seen any evidence that it was fixed in the HD.

My brother bought an original Kindle Fire, I tried it out and thought it's performance was horrible and I lost all interest in getting one.

The Kindle Fire HD performs completely differently and much much better, we have one and a Nexus 7. They both perform great, so well I would say that performance isn't a reason to choose one over the other.

What about the Nook HD? It has a higher resolution screen 1440 × 900, and the CPU is a step up with the 4470 over the Fire's 4460. Plus the advantage of having a microSDHC. The base model is only 8GB, but the 16GB version is only $229.

What about the Nook HD? It has a higher resolution screen 1440 × 900, and the CPU is a step up with the 4470 over the Fire's 4460. Plus the advantage of having a microSDHC. The base model is only 8GB, but the 16GB version is only $229.

The lack of an ecosystem is what hurts it but if you don't care about any of that then it's a good choice. The Kindle definitely has the ecosystem advantage.

What about the Nook HD? It has a higher resolution screen 1440 × 900, and the CPU is a step up with the 4470 over the Fire's 4460. Plus the advantage of having a microSDHC. The base model is only 8GB, but the 16GB version is only $229.

I'm more intrigued by the Nook HD+ 9 inch for $269.

If it can be made to work with google Play and Amazon instant video the main thing lacking is no camera for Video chat.

just picked up a Nexus 7 32 gig for $249...now time to learn how to use it...staples has a $25 online order coupon right now so you can get it for $224 shipped...I was not around to wait for shipping ( on the road) so I went to OD and picked it up in person